Eyeglasses are known in the art which are provided with color enhancing lens. Some such type of eyeglasses are disclosed in U.S. Pat. Nos. 3,586,423 and 3,701,590 issued to Harry I. Zeltzer respectively on Jun. 22, 1971 and Oct. 31, 1972, and are directed to eyeglasses which aid color blind viewers. The eyeglasses include a single red corneal contact lens which covers only one eye and which transmits light only in the red zone while simultaneously permitting the "uncovered" eye to receive the color deficient image of an object which is normally associated with color blindness.
U.S. Pat. No. 4,300,819 issued to Donald E. Taylor on Nov. 17, 1981 is directed to eyeglasses similar to that disclosed in the above-discussed Zeltzer patents but provides the lens with reflective surfaces to make the colored lenses worn by a color blind person appear conventional so that "other observers will be unable to discern that the eyeglasses are specially made for color blindness or that they employ lens elements of different colors."
The present invention is directed to a color enhancing lens disposed for covering at least one eye of an observer (wearer). The other eye of the observer, which is non-color enhanced, may be left uncovered, or covered with a lens which will pass more than fifty percent of the wavelength of a selected color which is to be enhanced (highlighted). The color enhancing lens allows passage, to the eye, of a predetermined percentage (minor portion--less than fifty percent) of reflected light of the selected wavelength from the same object to the eye of the observer. The brain, in its attempt to make sense of this conflict interprets the difference as a quickly flickering reflection from the object which is of the selected wavelength. The color enhancing lens is itself provided with a selected color which will block substantially all portions of the visible light color spectrum except the selected portion of the spectrum in which the object reflects. For example, for seeing red, the color enhancing lens would be blue, cyan or green having the ability to limit the red portion of the color spectrum (that part of the spectrum between 6000 angstroms and 7000 angstroms) to, preferably, between 10% to 30% of the red passing the lens (filter). The other eye could be left unaided or covered with a lens that would preferably pass from 70% to 100% of the red portion of the color spectrum, between 6000 angstroms and 7000 angstroms.
A particular application of this principle is set forth wherein a pair of eyeglasses is provided with a lens which permits a wounded animal (such as a deer) to be tracked by a hunter. Sometimes, a hunter may only wound a deer or other hunted animal and the only way to recover the animal is to track the blood trail of the wounded animal. The principles of the present invention contemplates a frame (such as an eyeglass frame, for example) which supports a lens which blocks a major portion of reflected light in the red (blood colored) portion of the visible light color spectrum to one eye, while allowing a major portion of the light in the red portion of the visible light color spectrum to be received by the other eye.
Typically, when one eye receives a color image, the brain expects the same reception from the other eye with only a slight deviation as to reception angle and very slight color or shading due to the slightly different viewing angles of the eyes. These two differences provide for depth perception.
The device of the present invention provides a different problem for the brain to interpret. One eye is seeing one color (red, for example) and is sending this signal to the brain. The other eye, because of the limiting filter over it, is seeing the same object but is sending a vastly different color interpretation to the brain (dark red to black, for example). The brain, in its attempt to make sense of this conflict, seems to alternate rapidly between the two different colored images, and, in doing so, the perception is a quickly flickering color in the same position. When used as an aid in tracking a trail of blood left by a wounded animal, the device of the present invention allows a person to detect red on green or brown grass in very small quantities even when the ground is wet from dew. The device is also an improvement over the use of flashlights or lanterns in blood tracking since the artificial light makes everything shine.
By proper selection of the lens one can provide a color enhancing lens system which will work for other colors. To achieve this result, it is necessary to select a color filter for one eye that will preferably block from 70% to 90% of the color to be highlighted. The other lens for the other eye is selected to preferably pass 70% to 100% of the same color. In this manner all colors in the visible spectrum can be selectively highlighted to the observer. Also, the lens that is non-blocking of the desired color can be selected so as to block or subdue other undesired colors to further enhance the reception and detection of the desired color .